Radio receiving apparatus



June 19., 1928- a. E. J. OAKLEY ET AL RADIO RECEIVING APPARATUS Filed Dec. 2, 1926 INVENTORJ ATTORNEY Patented June 19, 1928.

UNITED STATES 1,674,218 PATENT OFFICE.

GEORGE EDWARD. JOHN OAKLEY, F SLOUGH, AND KENNETH GRAHAM SMITH, OI

MAIDENHEAD, ENGLAND, ASSIGNOR-S TO BRANDES LABORATORIES, INC, OF NEW- ARK, NEW JERSEY, A CORPORATION OF NEW JERSEY.

RADIO RECEIVING APPARATUS.

Applicatiomfiled December 2, 1926. Serial No. 152,197.

Our invention relates broadly to radio receiving apparatus and more particularly to apparatus for tuning a. radio receiver to selected signaling frequencies. I

One of the objects of our invention is to provide a tuning apparatus for radio receivers which is effective over the broadcast range of signaling frequencies and also effective at a signaling frequenc which is m widely separated from the broa cast range of frequencies.

Another object of our invention is to provide a tuning apparatus by which a radio receiver'may be adjusted to-respond to a plurality of frequencies within a selected band of frequencies and selectively respond, to a definite frequency which is removed in the frequency scale from the aforementioned band of frequencies.

Still another object of our invention is to provide a construction of tuning apparatus whereby the coupling between a radio frequency energy collecting circuit and a radio receiving circuit may be modified for enabling the receiver to operate over a selected band of frequencies or to respond to a def inite frequency substantially removed from the band of frequencies.

Our invention is directed to a receiving apparatus in which regenerative amplification is secured in an electron tube circuit system with separate inductance elements arranged tobe effectively included in the radio frequency energy collecting circuit with which a reaction coil of the regenerative amplification system may be selectively associated with either of th inductance elements for securing response over a selected band of frequencies or at a frequency which is widely separated from the selected band of frequencies.

Our invention will be more fully understood from the specification hereinafter following by reference to the accompanying drawings in which:

Figure 1 is a side elevation of the reaction coil mounting for the tuning apparatus of our invention; Fig. 2 is a view taken on line 33 ofFig. 1 showing a part of the reaction coil mounting in cross-section.

The receiving apparatus of our invention has been developed to meet the requirements of the law, whereby a broadcast radio receiver may be responsive to signals of long wave len 11 while the same receiver is useful for roadcast radio reception over a selected band of frequencies.

Tuning condenser 4 is shown in circuit with the antenna 3, the antenna connecting to the grid circuit of the electron tube 1 through the grid condenser and high resistance path 12. Tuning condenser 11 is arranged across the input circuit. The three-way inductance comprises windings 5, 9 and 10. The winding 5 responds to long waves and is denoted as the Daventry coil B in Figs. 2 and 3. The winding 9 responds to short wave lengths and is designated as coil A in Figs. 2 and 3. The reaction coil is designated at C in Figs. 2 and 3 as supported on a frame 29 which may be swung in an are upon the support 28 extending from arms 27 under control of the shaft member 26 which is journaled at 24 and 25 in the side portions 22 of the three-way coil mounting. Switching devices 6 and 8 are provided for effectively including a selected one of the windings 5 M19 in the receiving circuit. The receiving circuit is connected to ground as represented at 7. The

output circuit of the detector tube 1 includes the react-ion coil 10 and the primary winding of the audio frequency transformer 14, the secondary winding 16 of which connects to the input circuit of the amplifier tube 2.

In order toplacea proper bias potential upon the grid of the amplifier tube 2 a battery 19 under control of rheostat 20 is arranged in the input circuit of the tube 2. The high potential for the output circuit of tube 1 and the output circuit for tube 2 are obtained from battery source 18 with terminal 17 leading to the telephone or loud speaker circuit. A battery 21 is provided for heating th cathodes of the tubes 1 and 2.

Referring to Fi 1 of the drawings the coil A constituted y the short wave winding 9 is supported from themounting 22 by means of lateral plate 23 while coil B constituted by the long wave winding 5 is mounted from the laterally extending plate portion 24 in an axis which is normal to the axis of the winding 9. The reaction coil 10 designated at C may swing about a pivot with the shaft 26 as an axis to rmit the coupling of reaction coil 10 wit winding 9 orthe independent coupling of reaction coil 10 with the winding 5.

Winding '9. or short wave coil A is connected in circuit and rendered effective by the closing of contacts connected with the coil. Reaction winding 10 designated at coil C is swung near to coil A as shown in Fig. 1 for the securing of regenerative effect. When long wave length signals are to be received the short wave coil 9 is disconnected from the tuning circuit and the long.

wave coil 5 is' effectively connected in the tuning circuit by the closihg of another set of contacts and then the reaction coil C 'is swung towards the short wave coil B and regenerative action secured by the coupled relationship of windings 10 and 5. The influence of electromagnetic and electrostatic effects of windings 5 and 9 with respect to each other is substantially eliminated by means of the mounting of the windings in axes which are normal to each other. When coil 10 is inductively coupled with coil 9 the coil 5 is substantially inert and when wind ing 10 is inductively coupled to winding 5 thewinding 9 is substantially inert.

The structure of tuning apparatus illustrated herein has been found to be verypractical in its operation, and while we have de-' members disposed in planes at right angles one to -the other, each of said laterally extendin members serving to support separate in uctance units with their axes normal one to the other and a separate coil member pivotally mounted in said frame andbeing arranged to be swung intocoupled relationship with a selected one of said aforementioned inductance units.

2. Tuning apparatus for radio receiving systems comprising a frame constituted by a pair of side members, laterally extending members disposed between said side members and in planessubstantially at an angle with respect to each other, said laterally extending members providing means for supporting a pair of independent inductance coils with their axes substantially normal one to the other, a rotatable shaft member journaled adjacent opposite ends thereof in said side members, said rotatable shaft member carrying an inductance coil arranged to fit concentrically within each of said aforementioned inductance coils whereby said last mentioned inductance coil may be independently coupled with aselected one of said aforementioned inductance coils.

3: Tuning apparatus comprising a frame structure constituted by a pair of side members, laterally extending members interconnecting said side members, cylindrical coil supports carried by each of said laterally extending members with the axes of said supports disposed substantially normal one to the other, windings carried by said coil supports, a rotatable shaft member journaled adjacent opposite ends thereof in said side members in a position between said aforementioned coil supports, a se arate coil support carried by said rotatable s aft member, and an independent winding on said separate coil support arranged in such manner thatsaid separate coil support may be positioned concentrically within a selected one of said first mentioned coil supports for establishing a coupled relationship between said independent winding and a selected one of the windings carried by said first mentioned coil supports. y

In testimony whereof we aflix our signatures.

' GEDRGE EDWARD, JOHN OAKLEY.

KENNETH GRAHAM SMITH. 

